A substantially achromatic multiple element compensator system for use in
wide spectral range (for example, 190-1700 nm) rotating compensator
spectroscopic ellipsometer and/or polarimeter systems. Multiple total
internal reflections enter retardance into an entered beam of
electromagnetic radiation, and the elements are oriented to minimize
changes in the net retardance vs. the input beam angle resulting from
changes in the position and/or rotation of the system of elements.